Optical waveguides fabricating processes of the above type are known, (Essay: "Production of preforms for optical fibers" Vol. 62, no. 3/4, Electrical Communications of 1988).
The effort in known optical waveguides is concentrated on producing an optical waveguide core with a precisely circular cross-section. Any deviation from the circular geometry of the optical waveguide leads to problems with the propagation of light, and therefore to problems with the transmission of the information.
The light that is used to transmit the information may have two perpendicular directions of polarization, which have equal use in the transmission of information through an optical waveguide with a precisely circular core.
However, with the transmission of information through optical waveguides, instances of application can be envisioned in which only one direction of polarization is desired, and the other direction of polarization is suppressed, because in this way a signal can be routed over a long distance without major interference.